The present invention relates to a method and an apparatus displaying characters and/or images using the rotation of light emitting diodes (LEDs), and more specifically, to an apparatus for displaying a bit map image from a basic display unit of 24 dots (vertical)xc3x97256 dots (horizontal)xc3x971 (color) up to a display unit of 64 dotsxc3x97512 dotsxc3x973 (full color) or more.
A conventional image display apparatus is shown in PCT Application No. PCT/EP97/03145, filed on Jun. 17, 1997 by Lumino Company in Germany. This image display apparatus comprises a casing made of a transparent and/or semitransparent material, which contains an electric motor. The electric motor has a rotary shaft rotating around a symmetry axis. Rotatably mounted to the motor shaft is a rotary wing assembly on which a series of LEDs are attached in the vertical direction of the motor shaft.
The conventional image display apparatus further comprises a logic control board for controlling the above LEDs, and a photoelectronic measurement device for measuring a rotation speed of the rotary wing assembly. The photoelectronic measurement device includes a transmitter/receiver unit mounted to a rotary part of the apparatus at its one end and to a stationary part of the apparatus at its other end, both ends being spaced at a short distance from each other and facing each other at the opposite sides.
The conventional image display apparatus further comprises a mechanical balance unit provided at a position symmetrically opposite to the rotary wing assembly. The balance unit has an arbitrary sectional area and may preferably be a bar adjustable in length. The conventional apparatus keeps its balance by adjusting the length of the bar, which maintains its horizontal state while the motor rotates, or while the apparatus is operated.
This display apparatus is adapted to display a bit map image in a basic display unit of 16 dots (vertical)xc3x97256 dots (horizontal)xc3x971 (color). Further, the apparatus is disadvantageous in that it provides no color expression and is very short in life due to mechanical defects. The motor shaft of the display apparatus is asymmetrical around the symmetrical axis.
Another conventional technique related to the image display is disclosed in Japanese Patent Laid-open Publication No. Heisei 2-61693 (Mar. 1, 1990), which shows a contactless energy transfer technique for supplying power from a generator to a control unit.
Another conventional technique related to the image display is disclosed in PCT Application No. PCT/EP98/00284, filed on Jan. 20, 1998 by Lumino Company in Germany, which shows a display apparatus wherein the transfer of energy to a logic control unit for control of LEDs is conducted in a contactless induction manner as in the above Japanese publication. This display apparatus is desirable to use a generator, transformer or electrostatic capacitor for the energy transfer, but has a disadvantage in that it has no feedback arrangement for accurately performing the energy transfer.
The above display apparatus employs a pole shading motor, which is simple in construction, but low in efficiency, resulting in a large amount of heat being generated. The pole shading motor further employs a light amateur as its rotor, thereby exhibiting a severe variation in its rotation speed due to an air resistance or weight even after it reaches a predetermined speed.
The above conventional display apparatus further comprises a serial electrically erasable and programmable read only memory (EEPROM) as a backup memory for storing data to be displayed by the logic control unit for the control of the LEDs. As a result, a larger amount of data to be stored increases the amount of memory load and, in turn, a processing time.
FIG. 1a is a front view of a conventional LED, indicated by the reference numeral 120. As shown in this drawing, the LED 120 consists of three parts, a head 122, a flange 124 and legs 126, configured in one LED chip, and is of a single-color type. In the case where a plurality of LEDs, for example, sixteen LEDs, each of which is the LED 120, are mounted to a rotary wing assembly, the adjacent ones of them have a gap therebetween resulting from the flanges 124 over the legs 126, which leads to a reduction in resolution, thereby making it impossible to express a fine image or characters. Further, adjacent pads cannot help being arranged apart from each other at a distance resulting from the flanges 124, thereby causing the LEDs 120 to be arrayed on both sides of the pads. Here, the pads signify copper foils on which the LED legs 126 are soldered and fixed.
In a conventional display apparatus, a logic control unit is inserted into a motor shaft via a hole. This hole is not positioned in the center of the circular portion but leans toward the rear of the circular portion, and this circular portion has no cover, thereby making it difficult to assemble the apparatus.
Further, the conventional display apparatus is adapted to adjust the length of a balance plate so as to keep its balance during its rotation. Also, the motor body is not rotated symmetrically about the motor shaft. Moreover, only the logic control unit is coupled with the motor shaft such that it rotates.
The conventional display apparatus comprises a transmitter and a receiver mounted to the lower part of the logic control unit separately from each other. This apparatus further comprises a reflector mounted to its stationary part. With this construction, the logic control unit is adapted to detect a light beam reflected by the reflector. As a result, a photoelectronic measurement device of this display apparatus is degraded in performance due to noise, etc., as compared with a transmission-type device.
Conventionally, a secondary voltage is generated and transferred either in a contact manner or in a contactless manner. A contact-type secondary voltage generation/transfer method, for example, a brush method is adapted to transfer an external direct current (DC) supply voltage to a secondary side through a contact surface of a brush. A contactless-type secondary voltage generation/transfer method, for example, a generator method is adapted to utilize a voltage induced in a generator with rotation as a secondary voltage. In this case, the generator acts as a converter for converting an alternating current (AC) voltage into a DC voltage. Also, a regulator is used to convert a voltage of +8V or more into a voltage of +5V. However, in the contactless-type method, a secondary voltage is not induced under the condition of no rotation, which leads to a reduction in rotation speed and occurrence of noise when the amount of load on the secondary side is increased. Therefore, it is impossible to raise the resolution by increasing the number of LEDs and, in turn, the number of dots.
In the contact-type secondary voltage generation/transfer method, no distinction is made between a primary voltage and a secondary voltage. The contactless-type secondary voltage generation/transfer method employs a personal computer (PC) serial communication port for inputting external data.
The conventional display apparatus has no front board acting as a keyboard. Further, this apparatus has a unitary body and a display bulb colored only brown.
Therefore, it is an object of the present invention to provide a method and an apparatus for displaying characters and/or images to overcome the above problems.
In accordance with one aspect of the present invention, the above and other objects can be accomplished by a provision of a character and/or image display apparatus, comprising a rotary wing assembly consisting of a plurality of light emitting diodes (LEDs) and a rotary wing; a logic control unit controlling the LEDs of the rotary wing assembly to allow the LEDs to display desired characters and/or desired images; a balance unit consisting of a balance plate and a balance weight, the balance unit being assembled with the logic control unit at a position opposite to the rotary wing assembly so as to accomplish a desired balance of the rotary wing assembly regardless of a difference in the center of gravity between the rotary wing assembly and the logic control unit during a rotating action of the rotary wing assembly; a motor unit consisting of a stator, a rotor, a hollow motor shaft having an axial passage and extending through both the stator and the rotor and being connected to both the rotor and the logic control unit at its opposite ends so as to rotate the rotary wing assembly, the logic control unit and the balance unit at the same time by a rotating force of the rotor, and a rotor holder used for locking the logic control unit to the motor shaft; a switch mode power supply (SMPS) used for supplying a direct current (DC) power to the logic control unit in a contactless manner, and mounted to a lower end of the motor shaft so as to be rotatable together with the motor shaft at the same time, the SMPS consisting of a primary board and a secondary board, the primary board transmitting both external alternating current (AC) voltage and external input data to the secondary board, and the secondary board being electrically connected to both the rotary wing assembly and the logic control unit through electric wires passing through the axial passage of the hollow motor shaft, thus transmitting the power and data to both the rotary wing assembly and the logic control unit; a data communication unit consisting of a modem board and an RS-232 board, and being used for transmitting external input data to the logic control unit; a display bulb covering the top of the rotary wing assembly, the logic control unit and the motor unit while forming a sealed space in the bulb, the display bulb allowing a user to observe characters and/or images displayed by the LEDs from the outside of the bulb; and an external casing mounted to a lower end of the display bulb and encasing the motor unit, the SMPS and the data communication unit.
The logic control unit of the present invention may include a micro controller; a backup memory for storing data necessary to the operation of the display apparatus, the backup memory being of a nonvolatile type; a working memory for reading the data stored in the backup memory; a data latch buffer for latching data from the working memory by a predetermined number of vertical dots; a latch clock generator for supplying clock data to the data latch buffer in response to an input/output control signal from the micro controller; an LED data driver for reading data from the data latch buffer in response to the clock data from the latch clock generator; and an LED array for displaying data under control of the LED data driver.
Preferably, the balance between the rotary wing assembly and the logic control unit may be accomplished by adjusting the weight of the balance weight, and the balance weight may be covered with a balance weight cover at its top and bottom, thus being prevented from undesirably coming into contact with the display bulb or from scratching the display bulb during an assembling process of the display apparatus.
Each of the LEDs, preferably, may be free from a flange radially projecting outward from a sidewall of an LED mold of each LED and have one or more LED chips arrayed in one LED mold in a horizontal, vertical, diagonal, or triangular arrangement.
The logic control unit may be covered with a cover at its circular end portion to reduce noises and air resistance during a rotating action of the logic control unit, and the SMPS may be of a flyback type where a secondary side of the SMPS is turned on when a primary side thereof is turned off, and include an AC input unit; a DC converter for converting an AC voltage from the AC input unit into a DC voltage; a pulse width modulation (PWM) control/generation circuit for controlling the output of the DC voltage converted by the DC converter to generate a high voltage; a high voltage/low voltage converter for converting the high voltage from the PWM control/generation circuit into a low voltage; a smoothing circuit for smoothing the low voltage converted by the high voltage/low voltage converter; and an output voltage detector for detecting a voltage signal from the smoothing circuit and transferring the detected voltage signal to the PWM control/generation circuit.
The balance weight may be a screw-type balance weight or a compression-type balance weight.
The motor unit may be an induction motor unit, being rotatable at the same time with the stator and a motor casing of the motor unit being rotatable at the same time while accomplishing a rotational symmetry around the hollow motor shaft.
An electric wire and a data communication wire from the secondary board of the SMPS may pass through the passage of the hollow motor shaft prior to being connected to the logic control unit.
Further, preferably, the secondary board of the SMPS may be provided with a transparent optical sensor unit, the sensor unit being integrally formed with a light emitting part and a light receiving part for sensing both a rotating velocity of the rotor of the motor unit and an initial rotating point of the rotor.
An optical transistor may be mounted to a central position of a ferrite core, the optical transistor being used for optically receiving a variety of data transmitted through a power feedback signal IR (infra-red) of the secondary board of the SMPS or through a power feedback signal IR of the primary board of the SMPS.
The various data may be transmitted from cellular phones, pagers, FM tuners, digital radio systems, RS-232, modems, and keys.
The primary and/or the secondary ferrite core may be EE type formed in the shape of a circle or square.
The primary and/or the secondary ferrite core may form the secondary side of the EE or El core formed in the shape of a circle or square.
The primary and the secondary-side bobbins of the SMPS may be separated from each other, the secondary-side bobbin may be situated inside primary-side bobbin while being upwardly spaced somewhat apart from the primary-side bobbin, and the primary-side bobbin may be mounted to be fixed and the secondary-side bobbin is mounted to be rotated.
The primary and the secondary-side bobbins of the SMPS may be laterally spaced somewhat apart from each other, and the primary-side bobbin of the SMPS may be mounted to be fixed and the secondary-side bobbin of the SMPS may be mounted to be rotated.
The modem board may be connected to external communication means via stereo- or mono-phone jacks, the stereo- or mono-phone jacks being mounted on the inside-support bracket.
In accordance with another aspect of the present invention, there is provided a character and/or image display method comprising the steps of a) applying power to a character and/or image display apparatus and setting up input/output port values and initialization values; b) initializing all LED values and clearing a screen; c) reading initial picture data from a nonvolatile backup memory; d) writing the data read from the backup memory into a working memory; e) reading initialization data from the working memory; f) displaying an initial picture and performing a still mode until a rotation speed of a motor becomes stable; g) reading data other than the initialization data from the working memory; h) sequentially performing modes corresponding to commands contained in the read data; and i) repeating the above steps g) and h) until all commands stored in the working memory are processed.
Preferably, the commands may include a data reception command, a data storage command, a line back and forth command, a frame up command, a frame down command, a reset command and a complex command.
As described above, the method and the apparatus for displaying characters and/or images of this invention has the improved operational effect as follows:
1. This apparatus and method of this invention effectively displays data using bitmap images.
2. In the apparatus and method of this invention, one or three LED chips are mounted to one LED, and so it is possible to increase the number of LED chips mounted within the same area in comparison with conventional apparatuses and methods, thus displaying beautiful characters and/or images in a variety of colors.
3. The logic control unit 200 is covered with a cover 260, and so it is possible to overcome the problem caused by an air resistance and to accomplish a central beam scanning effect.
4. It is possible for the apparatus and method of this invention to accomplish a desired balance of the rotary wing assembly by properly controlling the weight of the balance weight 420.
5. The motor unit is an induction motor unit, with the rotor of the motor unit accomplishing a rotational symmetry around the motor shaft 330. In addition, the motor stator 320 integrated with the motor casing is used as the rotor 310 of the motor, while an armature is used as the motor stator 320. Such an induction motor is remarkably improved in its operational efficiency in comparison with pole shading motors, and has an improved flywheel effect, thus being less likely to be changed in its rotating velocity. In addition, the motor shaft 330 is a hollow shaft defining an axial passage and allowing an electric wire to pass through.
6. In the apparatus of the present invention, the secondary-side power is produced by the SMPS using a feedback signal.
7. In addition, the feedback signal and bitmap image data of the SMPS are transmitted from the center of the ferrite core designed to accomplish a rotational symmetry.
8. In the apparatus and method of the present invention, the ferrite core and bobbin between the primary and secondary boards of the SMPS are locked together while desirably reducing a leakage of current in comparison with the prior art.
9. The secondary board of the SMPS is provided with a transparent optical sensor unit 511, which is integrally formed with a light emitting part and a light receiving part for sensing both the rotating velocity of the motor rotor and the initial rotating point of the rotor. It is thus possible to easily install the sensor unit in the apparatus. The sensor unit is also less likely to be influenced by external noises and has a high response velocity.
10. The apparatus has an expected life span longer than that of conventional apparatuses, and is not likely to be changed in its rotating velocity regardless of a change in load.
11. It is possible for the apparatus of this invention to easily and simply fabricate the circuit of the logic control unit 200 since the apparatus uses the SMPS.
12. The apparatus has a high efficiency, and so it preferably generates a small amount of heat and is less likely to allow a leakage of current, thus being reduced in its power consumption.
13. The apparatus has a high brightness and a high resolution, and so it has a bright and clear display surface.
14. In the apparatus, the motor can be usable semipermanently.
15. Since the apparatus of this invention is preferably reduced in its power consumption, it saves money for power costs.
16. In the apparatus of this invention, a memory, having both the SRAM function and the EEPROM function, is used as the backup memory, and so it is possible for the apparatus to effectively perform a parallel data processing operation. Therefore, the apparatus can quickly process the data without requiring a memory having an enlarged capacity even though it is necessary to process a very large quantity of data.